Control means for cutting flat surfaces

ABSTRACT

A ELECTRON CIRCUIT CONTROL MEANS FOR PRODUCING RANDOM SPACED SURFACE CUTS AND PANELS OR BOARDS TO SIMULATE A HAND HEWN PRODUCT. A LINE OF CUTTER WHEELS IS POSITIONED ABOVE THE PANEL OR BOARD SURFACE AND CONTROLLED ELEMENTS MOVE TOWARD THE PANEL SURFACE TO REMOVE A SMALL PORTION OF THE SURFACE. THE CUTTER WHEEL MOTION IS CON-   TROLLED BY A COMBINATION OF ELECTRONIC OSCILLATORS, THE FRE QUENCES OF WHICH VARY WITH TIME TO PRODUCE A RANDOM PATTERN OF CUT AREAS. THE CUTTERS ARE ALSO MOVED TRANSVERSELY BY A SIMILAR CONTROL MEANS.

N. A. MuRPHr-:Y ErAL 3,616,826

CONTROL MEANS FOR CUTTING FLAT SURFACES `d: Sheets-Sheet 1 www ,QN NJUTI NORMAN A. MURIHEY RONALD w. SOUTHWORTH Nov. 2, wm N, A. MURPHEY ErAL 3,616,826

CONTROL MEANS FOR CUTTING FLAT SURFACES 4 Sheets-Shawl'. 2

Filed May 6, 1970 Nov. 2, 1971 N. A. MURPHEY ETAL 3,615,826

CONTROL MEANS FOR CUTTING FLAT SURFACES 4 Sheets-Sheet .'5

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Nov. 2, 1971 N. A. MURPHEY ETAL 3,616,826

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T[/24 5F68 1cUTTER5 rNvr-:N'roRS NORMAN A. MuNmmv RONALD w. som'uwon'ru United States Patent O 3,616,826 CONTROL MEANS FOR CUTTING FLAT SURFACES Norman A. Murphey, Anderson, and Ronald W. Southworth, Redding, Calif., assignors to U.S. Plywood- Champion Papers Inc., New York, N.Y.

Filed May 6, 1970, Ser. No. 35,011 Int. Cl. B27c 5 /02 U.S. Cl. 144-136 10 Claims ABSTRACT OF THE DISCLOSURE An electronic circuit control means for producing random spaced surface cuts on panels or boards to simulate a hand hewn product. A line of cutter wheels is positioned above the panel or board surface and controlled elements move toward the panel surface to remove a small portion of the surface. The cutter wheel motion is controlled by a combination of electronic oscillators, the frequencies of which vary with time to produce a random pattern of cut areas. The cutters are also moved transversely by a similar control means.

An electronic circuit control means for producing random spaced surface cuts on panels or boards to simulate a hand hewn product. A line of cutter wheels is positioned above the panel or board surface and controlled elements move toward the panel surface to remove a small portion of the surface. The cutter wheel motion is controlled by a combination of electronic oscillators, the frequencies of which vary with time to produce a random pattern of cut areas. The cutters are also moved transversely by a similar control means.

The use of hand hewn beams and panels adds a rustic efiect to any building, both inside and out. There is a considerable demand for textured panels having such a surface, simulating old beams and planks which were hewn out of logs lby hand with an axe or adze. Prior attempts to produce such panels by automatic machines has always resulted in a repeated pattern which is obvious and destroys the rustic effect. The present invention uses five oscillators which are designed to drift in frequency output by small increments depending upon temperature, voltage supply and the variable characteristics of circuit components. The result is a pattern of surface cuts which is random and never repeats itself.

This invention is an improvement over the panel or board cutting control means disclosed in patent application Ser. No. 579,624, filed Sept. 13, 1968 and assigned to the assignee of this application, i.e., U.S. Plywood- Champion Papers Inc.

One of the features of the present invention is the complete automatic operation wherein the pattern of the cuts is provided by an electronic circuit, operated in random fashion.

Another feature of the invention is the use of a transverse control means to move the cutters across the width of the board to increase the rustic effect.

For a better understanding of the present invention, together with other details and features thereof, reference is made to the following description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a plan view of the machine embodying the invention.

FIG. 2 is a cross sectional view of the machine shown in FIG. l and is taken along line 2-2 of that figure.

FIG. 3 is a clock circuit diagram showing all the control 3,616,826 Patented Nov. 2., 1971 circuits and the hydraulic control means for operating the cutters.

FIG. 4 is a schematic diagram of connections of a rate multiplier for increasing the rise time of the pulses generated by the oscillators.

FIG. 5 is a schematic diagram of connections of a limit switch for reversing the direction of a stepping motor.

FIG. 6 is a series of graphs showing the relationship of the oscillator waves and some of the pulses.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. l, 2, and 3, the cutting machine comprises two side supports 10, 11 and a flat bed plate 12. Supports 10 and 11 act as bearings for four sprocket wheels 13 which mesh with two endless chains 14 and 15, adapted to engage a panel board 16 and push it under the cutter assembly. The sprocket wheels 13 are coupled to shafts 17 and one of the shafts 17 is secured to another sprocket wheel 18 which is turned by a motor 20.

The cutting assembly is supported generally between two Vertical plates 21, 22 and includes a plurality of cutting wheels 23 for making the cuts in the panel board 16. The cutting wheels are each rotatably mounted on a yoke 24 and a common motor 27. The cutter wheels 23 are supported vertically by an adjustable post 28 and an eccentric 30 secured to a transverse shaft 31. The shaft 31 is turned by a bell crank 32 (see FIG. 3), coupled to a yoke 33 and a hydraulic piston in a cylinder 34. The cutter wheels 23 and their yokes 24 are supported horizontally lby strips 35 having one end pinned, by a at or upstanding pin, to a transverse bar 36. The cutter wheels are lowered to cut the panel each time the shaft 31 is turned.

The transverse position of the cutter wheels 23 is controlled by the position of bar 36. This bar is coupled to an eccentric 37 turned by a stepping motor 38. The stepping motor 38 is powered by a hydraulic system but controlled by an electric circuit. The electric portion of this unit may be a two phase motor which rocks either clockwise or counterclockwise to open selected parts for the fluid under pressure. The result is an incremental motion of shaft 40 (FIG. 3,) to move the eccentric 37 and all the cutter wheels. The side motion of the wheels is necessary to create a random pattern of cuts on the panel board. There may be times when the side motion of the cutter wheels 23 must Ibe contained within certain limits, depending upon the type of board being cut. A limit switch 41 is provided for this purpose. It has an armature 42 positioned within a U-shaped bracket 43 which is secured to bar 36. When the stepping switch moves the bar 36 too far in either direction, the armature 42 is moved to a new position and the direction of the motor 38 is reversed. The armature 42 (see FIG. 5) is held in its actuated position by a spring detent 44.

The electronic system which controls the cutter positions is shown in FIG. 3 where `four variable oscillators 45, 46, 47, and 48 control the vertical motion of the |cutter wheels 23. Each oscillator Igenerates an alternating current having a frequency less than cycles per second. Each oscillator is subject to gradual change of frequency of its output. 'Each oscillator is connected to a binary counter 50, 51, 52, and 53 having four output conductors. As each counter is activated by a positive pulse from its oscillator it applies a negative pulse to one of its four output conductors in a sequential manner. Counters 50 and S1 send their output pulses to a first pulse rate multiplier 54 while the other counters 52 4and 53 send their output pulses to a second pulse rate multiplier 55. The counter outputs are sent to the pulse rate multiplier to alter the wave shape and produce a fast rise time. The multiplier circuits also act as partial summation circuits.

FIG. 4 shows the details of the pulse rate multiplier circuits. There are four upper input terminals 56, 57, 58, and 59. There are also four lower input terminals 61, 62, l63, and 64. A single output terminal 65 is connected to one of the bistable flip-ops, either 66 or 67. The rate multiplier circuit includes four identical subcircuits to the left of dotted line 68, each including two transistors and two input terminals. Each of these four circuits acts in a manner similar to a Schmitt trigger circuit. When there is no input one transistor 70 is conducting while the other transistor 71 is non-conducting. If a negative potential is now applied to terminal 56, conductance is switched from transistor 70 to transistor 71 but there is no output -because diode 72 does not pass the negative pulse. Now, if potential is removed from input terminal 56, transistor conductance returns to normal and a positive pulse is sent through diode 72 to the base of transistor 73. Transistor 73 is normally conducting but when the positive pulse is received it is made non-conducting and transistor 74 (normally non-conducting) is made conducting. A steep output pulse may be derived from terminal 75 but if an ampliiied pulse is desired, amplifying transistors 76 and 77 may be used to produce `a strong output pulse yat terminal 65. A feed-back circuit is used to further shape the output pulse. It is the connection between the collector electrode of transistor 716 and the base electrode of transistor 73. Diode 78 sends only positive pulses over this connection.

The outputs from the rate multipliers 66 and 67 are in the form of -variable frequency pulse trains. The pulses are of short duration and to maintain a control signal for Va longer time, bistable lip-flops are connected respectively to their output terminals. One pulse applied to flip-iiop circuit shifts conductance in the circuit and sends a substantial current pulse to solenoid Iwinding 80, attracting core 81 and opening valve 82. This action energizes the hydraulic cylinder 34 and operates yoke 33 and crank 32 to llower the cutter wheels 23 to remove portions of the panel 16 surface. When a second pulse is received from the rate multiplier, conductance is restored to normal, current over conductor 83 is reduced to zero and a sustained pulse is sent over conductor 84 to solenoid winding 85, attracting core '86 and opening valve 87. This action reverses the piston in cylinder 34 and raises the cutter wheels 23.

Oscillators 47 and 48, connected to counters 52 and y53 act in the same manner. The counters feed their pulses into the rate multiplier 55 and a similar series of random pulses is applied to the bistable flip-liep 67. The two output conductors 87 and 88 are respectively connected to AND gates 90 and 97 of these relays are connected in series with an oscillator 98, an amplifier 100, yand a stepping motor 38 which operates to shift the cutter wheels 23 across the width of the panel board. Switch 101 is normally closed so that AND gates 90 and 91 are connected to iiip-iiop circuit 66. This connection insures that there can be no transverse motion of the cutters when they are in their cutting position. The signals pass thru the AND gates uninhibited.

The hydraulic system used in this device has been employed because it is positive in action and produces considerable force to move the cutter wheels up and down and also from one side to another. However, it is obvious that electro-magnetic units can be adapted to do the same type of operation if desired. A motor 104 operates a pumping unit 105 to provide the required pressure in conduits 106 and 107. The stepping motor 38 is controlled by a series of electromagnetic valves to move bar 36 in increments to the right or left. The electromagnetic portion of this combination operates in the same manner `as a reversible AC motor and may be two phase, three phase, or be single phase with a capacitor starting winding. One method of operating this device is shown in FIG. where the oscillator 98 furnishes the 4 AC power to turn motor 38 and is connected to relay contacts 96 and 97. These contacts are connected to the end terminals of a primary winding 1111. The secondary win-ding 111 is connected to a power amplifier 1-00 and a reversing switch `41.

The operation of the stepping motor circuit is as follows: Let it be assumed that switch 10'1 is closed and that a pulse is applied from flip-flop 66 to both gates 9 0 and 91. Flip-flop `67 at this time sends a pulse over conductor 88 through AND gate 91 and relay winding 92. This action closes contacts 96 and sends AC current through the upper portion of primary winding 108. This power is amplified, sent through switch contacts 112 and 1113, to apply current of one phase to motor terminals 114. The other motor terminals 115 receive starting current direct from the oscillator in series with 4a capacitor 116. It is obvious from the circuit shown in FIG. 5 that closing contacts 97 instead of 96 reverses the current input to amplifier 100. Also, a shift in limit bar 42, opens contacts 112 and 113, closing contacts 117 and 1118 to reverse the current again.

The operation of the flip-flop, oscillators, and gates may be explained best by reference to FIG. 6. Oscillator45 sends alternations through binary counter to the rate multiplier terminals 56, 57, 58 and 59. As soon as any of the negative halves of the waves reach a certain level, the circuit is activated and a steep pulse 121 is sent from the lrate multiplier 54 to the iiip-flop 66. A similar action occurs in connection with oscillator 46 which generates two pulses 112 and 123 in the rate multiplier 54. Pulse 122 triggers the flip-flop `66 to 'generate a pulse 124 and operate valve 812. Pulse 124 is ended when the second wave from oscillator 46 sends a pulse 123 through the rate multiplier `54 and normalizes the flip-flop 66.

IOscillators 47 and 48 generating Waves 125 and 126 are coupled to the rate multiplier in a similar manner and produce pulses 127 and 128. When these pulses are combined in flip-flop 67 they produce a long pulse 1318 which is applied to gate 91 (switch 101 is closed). The AND gate 91 passes an output current only if two pulses are coincident at its input terminals. The result is two short pulses 131 and 132 which exist only when flip-flop 67 is on and flip-nop 66 is off. If switch 101 is open, the current pulses sent to motor 38 are the same as the output pulses of Hip-flop 67 on conductor 88.

It should be noted that the four oscillators 45, 46, 47, and 48 are all run at different frequencies. This arrangement has proved to be the best so far as producing a series of random cuts that do not show a reproducing pattern on the panel surface. The oscillator output waves are shown in FIG. v6 as being substantially sinusoidal. Such a wave shape is not necessary and almost any kind of wave shape can be used including square topped and triangular. Also, the shape of pulses 121, 122, 123, etc. from the rate multiplier are shown as square topped pulses. Depending upon the circuit constants, the pulses may have a fast rise time but trail olf in a manner as indicated by dotted line 121A. Such a change does not effect the result as only the leading edge of the wave is used to trigger iiipflops `66 and 67.

:Having thus fully described the invention, what is claimed as new and desired to be secured by Letters Patent of the United States is:

The embodiments of the invention in which an eX- clusive property or privilege is claimed are defined as follows:

1. Apparatus for treating the surface of a panel to prorvide thereon a plurality of randomly spaced shallow cavities comprising:

(a) a plurality of cutting wheels spaced along a cutting line and including a iirst power for driving the wheels to cut cavities;

(b) a means for passing the panel under the cutting wheels in a direction substantially at right angles to the cutting line;

(c) a second power means for lowering the cutting wheels at intermittent intervals to provide a plurality of randomly spaced cavities in the panel board surface, and

(d) a first control means for operating the second power means including two oscillators which produce currents having diiferent frequencies, a summation circuit for combining the oscillator currents, and a. pulse generating circuit for porducing control pulses which are applied to said second power means.

2. Apparatus as claimed in claim 1 wherein said second power means includes a pair of fluid valves in series with a source of uid pressure and a double acting hydraulic cylinder and piston, said piston coupled to the cutting wheels.

3. Apparatus as claimed in claim 2 wherein said iiuid valves are operated by solenoids.

4. Apparatus as claimed in claim 1 wherein said summation circuit includes a plurality of Schmitt trigger circuits for providing a fast rise time to the current alternations.

5. Apparatus as claimed in claim 2 wherein said summation circuit is coupled to a bistable Hip-flop to produce sustained output pulses for operating said fluid valves.

6. Apparatus as claimed in claim 1 wherein a third power means is provided for shifting the cutting wheels along the cutting line by steps, said third power means including a mechanical connection to a common shiftable bar which supports all of said cutting wheels.

7. Apparatus as claimed in claim 6 wherein a third power means includes a source of liuid under pressure, an hydraulic stepping motor, and an electromagnetic means for controlling the stepping motor.

8. Apparatus as claimed in claim 6 wherein a second control means operates the third power means to randomly shift the cutter wheels; said second control means includes two oscillators which produce currents having different frequencies, a summation circuit for combining the oscillator currents, and a pulse generating circuit for producing control pulses which are applied to said third power means.

9. Apparatus as claimed in claim 6 wherein a limit switch is provided for sensing the shift position of said common shiftable bar and for reversing the shift direction whenever a limit position is sensed.

10. Apparatus as claimed in claim 6 wherein two AND gates are connected in series with the shifting means for blocking the shift action until the cutting wheels are disengaged from the panel.

References Cited UNITED STATES PATENTS DONALD R. SCHRAN, Primary Examiner U.S. Cl. XJR. 144-l14, 2 

